Fluidized bed processes for the production of polymers has been well known in the art for several years. It is believed to have first been used in an industrial scale as early as 1968.
In this process, a polymerizable fluid generally enters the reactor at the bottom. There is generally an initial area where the polymerizable fluid is uniformly mixed prior to entering the fluidized bed reaction zone where the actual polymerization reaction takes place. The reactor generally has an outlet for removal of the polymer and separation of unreacted polymerizable fluid for recycling through the reactor.
In order to maintain a fluidized bed, a circulating gas stream is fed into the reactor from below. The circulating gas stream which consists essentially of unreacted monomers and inert materials is removed again at the top of the reactor, residual particles removed, gas stream cooled and put back into the reactor. The resultant polymer is removed from the reaction zone continuously or semi-continuously and treated further.
Various patents covering fluidized bed reactors and their components are known in the art. See, for example, U.S. Pat. Nos. 2,611,685; 4,518,750; 4,933,149; 5,059,664; 5,213,768; 5,401,890; 5,627,243; 5,723,401 and 6,441,108.
These various patents have adjusted the shape of the reactor, added components to separate chambers of the reactor or have added components to affect the flow distribution of the fluidized gas stream. Even with these changes, problems exist with the flow of the gas into the reaction vessel, as well as making sure that the side of the reaction vessel keeps clean of the formed polymer and that the particles carried in the polymerizable fluid do not fall back into the gas stream and potentially plug the reactor flow. The present invention provides an improved design for an angled annular deflector, an angular flow distribution bottom head and reactor vessel to facilitate the flow of gas into the reactor bed, the removal of contaminants and polymer from the sides of the wall, and the prevention of particle fall back into the gas stream.